[Dyslipidemia and suicidal risk in patients with psychiatric disorders]. / Dyslipidémie et risque suicidaire chez des patients avec maladies psychiatriques.

The aim of this work is to study the association between dyslipidemia and suicidal risk in patients with psychiatric pathology. Our study has involved 155 patients suffering from major depressive disorder and 124 schizophrenic patients aged 40.58±12.16 and 43.43±10.60 years, respectively. Total cholesterol (TC), triglycerides (TG) and HDL-c were determined by enzymatic methods, LDL-c was calculated by the Friedewald formula. Plasma cholesterol level was significantly lower among suicidal schizophrenic or depressive patients. There were no significant differences in the others lipid levels. The results of our study suggest that total cholesterol values less than 3.59mmol/L could be an indicator of suicide vulnerability in patients with schizophrenia or major depressive disorder.

Is low total cholesterol levels associated with suicide attempt in depressive patients?

BACKGROUND: Patients with major depressive disorder (MDD) have a high risk of suicide. Many pathophysiological factors involved in MDD and suicide such us a low cholesterol levels have been associated with MDD and increased vulnerability to suicide. In this study, we investigate the relation between lipid parameters and suicide risk in patients with MDD. METHODS: Plasma levels of total cholesterol, triglycerides, and high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) were determined in 160 patients meeting the DSM-IV-TR criteria for MDD (110 patients without suicidal behavior and 52 suicidal attempters) and 151 healthy controls. RESULTS: A significant decrease in plasma cholesterol levels was observed in the group of suicidal depressive patients compared to those without suicidal behavior (p < 0.001). For the other lipid levels (triglycerides, HDL cholesterol, and LDL cholesterol), there were no significant differences between suicidal and non-suicidal patients. CONCLUSIONS: Our study showed a significant decrease in plasma cholesterol levels in suicidal patients. This result support the hypothesis of the association of low plasma cholesterol level and suicidal behavior in patients with major depressive disorder.

Identification and characterization of a Fc receptor activity on the Toxoplasma gondii tachyzoite.

The Immunoglobulin (Ig) binding capacity of Toxoplasma gondii tachyzoites was investigated using fluorescence flow-cytometry analysis. Polyclonal mouse, human and rat immunoglobulins without specific anti-Toxoplasma activity bound to parasites in a concentration-dependent manner, saturating them at circulating serum concentrations. The immunoglobulin class and subclass specificity of binding was investigated using irrelevant monoclonal antibodies. IgM, IgA and IgG reacted with the parasite membrane. The attachment of mouse IgM to the parasite surface was hampered by mouse IgG1, IgG2a, IgG2b and IgG3. The binding of mouse IgG was proportionally reduced with increasing concentrations of mouse monoclonal IgM. The binding of murine immunoglobulin was diminished when in presence of human IgG. Purified Fc- but not Fab portions of immunoglobulins, fixed to parasites. Using labelled calibrated beads, the Ig binding capacity of parasites was estimated to be 6900 +/- 500 sites per tachyzoite. The Kd of the T. gondii Fc Receptor (FcR) activity was determined at 1.4 +/- 0.1 microM (mean +/- SEM). Such FcR activity was reduced by phospholipase C, trypsin and pronase treatment of the parasites. These data show a low affinity FcR activity on T. gondii tachyzoites which recognizes Ig of different species and isotypes and is likely supported by a glycosyl-phosphatidylinositol (GPI)-anchored surface protein of the parasite.

Simultaneous presence of different Borrelia burgdorferi genospecies in biological fluids of Lyme disease patients.

Oligonucleotide primers based on Borrelia burgdorferi sensu lato ospA gene sequences have been designed for use in the PCR to type all (SL primers) or each (GI to GIII primers) of the B. burgdorferi sensu lato genospecies involved in Lyme disease. These genospecies-specific primers were then used in the PCR on 24 biological fluids collected from 18 neuroborreliosis patients. Among the samples tested, 20 contained DNA from Borrelia garinii, 11 contained DNA from B. burgdorferi sensu stricto, and 10 contained DNA from Borrelia afzelii. In toto, 10 patients appeared to have been infected by a single genospecies and 8 were infected by more than one Lyme disease-associated genospecies. Serum specimens from six patients were absorbed with heterologous antigens and tested by Western blotting (immunoblotting). In four cases, residual immunodetection revealed specific epitopes of genospecies also detected by PCR; in two of them, the concordant results indicated pluri-infection of the patients. In the other two cases, Western blotting showed specific antibodies for two genospecies of Borrelia, while PCR detected DNA from only one. In summary, the data underscored the relatively high prevalence of pluri-infections in Lyme disease and confirmed the association of B. garinii with neuroborreliosis.

Assignment of Borrelia burgdorferi strains G25 and VS461 to the Borrelia garinii and Borrelia afzelii genospecies, respectively: a comparison of OspA protein sequences.

The nucleotide sequence encoding the Outer Surface Protein A (OspA) from two Borrelia burgdorferi sensu lato isolates, G25 and VS461, has been determined. On the basis of a phylogenetic analysis, strains G25 and VS461 were respectively assigned to the B. garinii and B. afzelii genospecies. Comparative analysis of OspA proteins from 26 different B. burgdorferi sensu lato strains involved in Lyme disease indicated a higher heterogeneity in the B. garinii genospecies than in the two other genospecies, B. burgdorferi sensu stricto and B. afzelii.